Smart battery device and charging method

1. A charging method, comprising: charging a battery unit with a charging current; obtaining a battery temperature of the battery unit; determining whether the battery temperature is lower than a first preset temperature; determining whether a current capacity of the battery unit is lower than a preset capacity when the battery temperature is lower than the first preset temperature; enabling a heating system to raise the battery temperature when the current capacity of the battery unit is lower than the preset capacity; determining whether a discharging current of the battery unit is greater than a preset discharging current when the current capacity is greater than or equal to the preset capacity; using a first value as a full charge capacity of the battery unit when the discharging current is lower than or equal to the preset discharging current; and using a second value as the full charge capacity of the battery unit when the discharging current is greater than the preset discharging current, wherein the second value is greater than the first value.

2. The charging method as claimed in claim 1 , wherein after the step of enabling the heating system, the charging method further comprises: determining whether the current capacity of the battery unit is greater than a minimum capacity; returning to the step of obtaining the battery temperature of the battery unit when the current capacity of the battery unit is greater than the minimum capacity; and enabling the battery unit to enter a shutdown mode when the current capacity of the battery unit is not greater than the minimum capacity.

3. The charging method as claimed in claim 1 , further comprising: using a first value as a full charge capacity of the battery unit when the battery temperature is greater than or equal to the first preset temperature.

4. The charging method as claimed in claim 1 , wherein after the step of using the second value as the full charge capacity of the battery unit, the charging method further comprises: determining whether the battery temperature of the battery unit is greater than a second preset temperature, wherein the second preset temperature is higher than the first preset temperature; and using the first value as the full charge capacity of the battery unit when the battery temperature of the battery unit is greater than the second preset temperature.

5. A battery device, comprising: a battery unit; a temperature sensing unit, configured to sense a battery temperature of the battery unit; a heating system, configured to heat the battery unit; a processing unit, configured to charge the battery unit with a charging current, obtain the battery temperature using the temperature sensing unit, and determine whether the battery temperature is lower than a first preset temperature, wherein the processing unit determines whether a current capacity of the battery unit is lower than a preset capacity when the battery temperature is lower than the first preset temperature, and the processing unit enables the heating system to raise the battery temperature when the current capacity of the battery unit is lower than the preset capacity; and a current sensing unit, coupled to the battery unit and configured to sense a discharging current of the battery unit; wherein the processing unit further determines whether the discharging current is greater than a preset discharging current when the current capacity is greater than or equal to the preset capacity, wherein the processing unit uses a first value as a full charge capacity of the battery unit when the discharging current is lower than or equal to the preset discharging current, and the processing unit uses a second value as the full charge capacity of the battery unit, wherein the second value is greater than the first value.

6. The battery device as claimed in claim 5 , wherein the heating system comprises: an energy storage unit, configured to store energy; a heating unit, configured to heat the battery unit; and a discharging switch, coupled between the energy storage unit and the heating unit, wherein the discharging switch conducts an electrical connection between the energy storage unit and the heating unit when the processing unit enables the heating system, whereby the heating unit heats the battery unit based on the energy of the energy storage unit.

7. The battery device as claimed in claim 5 , wherein the processing unit further determines whether the current capacity is larger than a minimum capacity after enabling the heating system, wherein the processing unit obtains an updated battery temperature using the temperature sensing unit when the current capacity is greater than the minimum capacity, and the processing unit enables the battery unit to enter a shutdown mode when the current capacity is not greater than the minimum capacity.

8. The battery device as claimed in claim 5 , wherein after using the second value as the full charge capacity of the battery unit, the processing unit further obtains an updated battery temperature using the temperature sensing unit and determines whether the updated battery temperature is greater than a second preset temperature, wherein the second preset temperature is higher than the first preset temperature, and the processing unit uses the first value as the full charge capacity of the battery unit when the updated battery temperature is greater than the second preset temperature.